TCP Server

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The TCP Server plugin allows you to accept and manage incoming connections over TCP. It enables you to maintain multiple client connections at once, focus on specific client communications through filters, and gain full control over the TCP socket, like TCP Connection. This makes it an invaluable tool for troubleshooting and debugging client-side projects.

Basic Setup

1. In IO Ninja, click the “New Session” dropdown and select “TCP Server”.

2. Set the adapter and port.

For example, if you wanted to listen for IPv4 traffic on port 2000, then you would set the adapter to “All IPv4 adapters” and the port to “2000”.

3. Click the “Listen” button to start listening to traffic.

4. Analyze the log as TCP requests are made to the server.

5. Adjust settings as needed via the “Settings” button (see “Settings” section below for details).

Settings

Setting	Description	Default
Adapter	Local network adapter to bind to. Pick one from the list of installed network adapters (or bind to all installed IP4 or all IP6 adapters at once).	All IPv4 adapters
Local port	Local port to bind to. Setting this to 0 auto-selects an available port.	8080
Reuse address	Allow multiple sockets to share the same local address. Maps to the SO_REUSEADDR socket option. Please note, the support and details of implementation for this option are highly platform-specific.	False
TCP Nagle algorithm	Delay transmission to reduce the number of small TCP packets. Maps to the TCP_NODELAY socket option.	False
TCP reset	Drop TCP connections abruptly with a TCP RST packet. Maps to the SO_LINGER socket option.	False
TCP keep-alives	Detect connection loss with TCP keep-alive probes. Maps to the TCP_KEEPALIVE socket option.	False
Read parallelism (Windows-only)	Maximum number of read requests to issue in parallel. Having more than one pending read at a time helps with increasing read throughput when incoming data arrives in rapid streams (after filling one user buffer, the kernel can immediately switch to the next one without any waiting). Increasing this number beyond 4 usually won’t yield any extra performance gains.	4
Read block size (B)	The size of each individual read block submitted to the underlying transport.	4KB
RX buffer size (B)	The full size of the incoming data (RX) buffer. Affects read throughput.	16KB
TX buffer size (B)	The full size of the outbound data (TX) buffer. Affects write throughput.	16KB
Keep read block size	Don’t merge read blocks in RX buffer. Incoming data blocks coming in quick succession can be merged together so that IO Ninja writes them to log as a whole. When this option is set to True, blocks are written to the log without merging, i.e., exactly as they are received from the underlying transport.	False
Keep write block size	Don’t merge write blocks in TX buffer. Outbound data blocks sent in quick succession can be merged together before submission to the underlying transport. When this option is set to True, blocks are submitted to the transport without merging, i.e., exactly as they are sent by the Transmit or Script panes.	False
RX buffer full notifications	Toggle warnings in log about the incoming data (RX) buffer getting full.	False

Note

An example of an adapter dropdown on a typical Windows laptop is shown below: